1. Field of the Invention
The present invention relates to an electrostatic brake dust collection assembly in which a charged collector plate collects airborne brake dust particles adjacent a brake rubbing interface of a vehicle brake assembly.
2. Background Art
The present invention addresses problems associated with the generation of airborne brake dust particles from the friction at a brake rubbing interface of a vehicle braking system when the brakes are applied. These airborne brake dust particles sometimes accumulate on aluminum wheels, and have become a recurring customer complaint issue on certain vehicle lines. This debris can be very difficult for customers to remove from an aluminum wheel, and occasionally causes discoloration of the wheels.
Also, the airborne brake dust particles generated by friction brakes may contribute to the atmospheric particulate matter (PM) load, a pollution criteria monitored by the Environmental Protection Agency (EPA).
It has been determined by brake dynamometer and chassis rolls dynamometer tests that a significant percentage of brake wear is in the form of airborne particulates. Brake dynamometer testing has shown that typically 80-90% of the total amount of material worn away from the brake discs and pads is airborne. Currently, the emission of particles in the PM10 (less than or equal to 10 xcexcm diameter) range is regulated for tailpipe emissions at 80 mg/mile, but that value is scheduled to be decreased to 10 mg/mile. Also, the EPA has proposed regulations for PM 2.5(xe2x89xa62.5 xcexcm diameter) particles. It has been determined that brake particles range from 0.4 to xe2x89xa710 xcexcm in aerodynamic diameter, with the mean diameter of 1-2 xcexcm. Brake wear dust potentially contributes to airborne PM load under current and future standards, therefore it is particularly desirable to reduce the release of airborne brake particles, even if this type of emission is not regulated.
The present invention provides a method and apparatus for reducing airborne brake dust particles by means of electrostatic, magnetic or electromagnetic dust collection.
Specifically, the present invention provides a vehicle brake assembly including a brake rubbing interface operative to slow a vehicle when activated. The interface produces airborne brake dust particles when activated. A dust collector plate is positioned in close proximity to the brake rubbing interface to collect the brake dust. A field generating system (such as a magnet, electromagnet, or charging circuit which generates electrostatic charge) generates a field so that the brake dust is attracted to the collector plate(s). Preferably, a charging circuit is used to generate an electrostatic field.
In alternative embodiments, the collector plates are magnetic or electromagnetic, and the iron in the dust particles is attracted to the magnetic or electromagnetic collector plate to reduce airborne dust particles.
A method of collecting airborne brake dust from a vehicle brake assembly in accordance with the present invention includes the steps of: a) providing a dust collector plate in close proximity to a brake rubbing interface of the vehicle brake assembly; and b) charging the collector plate to electrostatically collect airborne brake dust generated at the rubbing interface.
Accordingly, an object of the invention is to provide a method and apparatus for reducing airborne brake dust particles by electrostatically, magnetically or electromagnetically collecting the airborne dust particles closely adjacent the rubbing interface of the brake assembly.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.